1. Field of the Invention
The invention relates chiefly to a controlled valve (defined herein as a valve that operates under a control applied to it) with automatic opening and an aircraft comprising a controlled valve of this type.
2. Description of the Prior Art
There are prior art controlled valves which, under command or actuation, make it possible to let through a desired flow rate of a fluid between, for example, two chambers within which different pressures prevail. The prior art type controlled valves enable the regulation of flow rates or pressures. To enable stable regulation, the controlled valves are designed to work in a determined range of flow rates. Thus, it is not possible, by command, for example in the event of trouble, to get the pressures balanced by fast and complete opening of the controlled valve. Furthermore, the prior art type controlled valves act only upon external actuation. Thus, the malfunctioning of the external actuating device makes the controlled valve completely ineffective.
Thus, in the case of the most common uses, there are no safety means available to balance the pressures. In advanced technologies, such as, for example, in aeronautics, clack valves (defined herein as valves that open and shut automatically under pressure applied to them) are used: these clack valves are designed to open if the difference in pressure between their two faces goes beyond a predetermined threshold.
But, it turns out that the fact of having a clack valve or a controlled valve on a partition between, for example, two chambers or between one chamber and the outside, raises major problems. Firstly, there should be the space needed for the controlled valve and the clack valve. This is not always the case, notably if the controlled valves and clack valves have to be placed, for example, on a piping system that connects the tubes of chemical reactors or the points of a (for example) petroleum distillation tower.
Furthermore, the fact of making an opening needed for the controlled valve and the clack valve to pass through embrittles the wall. This embrittlement could be partially compensated for by a structure which is, for example, metallic, positioned around the controlled valve and the clack valve. However this metallic structure is costly and heavy. The additional weight has particularly serious implications in the context of aircraft manufacturing.